1. Field of the Invention
This invention relates to an improved fabric that is suitable for use in garments that provide protection against contact with hazardous substances. More particularly, the invention concerns such a fabric that includes at least two layers of a composite of a polyethylene film-fibril spunbonded sheet laminated to a three-layered thermoplastic film.
2. Description of the Prior Art
Workers in many industries need protection from hazardous substances. Some such protection is often in the form of a disposable, or limited use, outer garment which prevents worker's clothing or skin from contacting the hazardous material. Chemical-plant workers, asbestos removers, radioactive-contamination cleaners, chemical-waste disposal workers, and farmers handling various agricultural chemicals and pesticides are among the many users of such protective garments. Such garments need to be as impervious to chemicals as is consistent with safety, comfort and cost. Many of the disposable garments now available commercially provide only short-term protection. Chemicals can pass through such garments in but a few minutes, after which the wearer must immediately leave the work area, remove the contaminated clothing, and shower. Such short-term protection results in lost production time and, more importantly, in unwanted exposure of the worker to the hazardous substances.
Goldstein, U.S. Pat. No. 4,272,851, discloses protective garments made of spunbonded, polyethylene nonwoven sheet (e.g., "Tyvek", sold by E. I. du Pont de Nemours and Company) which may be coated or laminated on one one side with a polyethylene film. Steuber, U.S. Pat. No. 3,169,899, discloses detailed characteristics and a method of manufacture of the spunbonded olefin sheets made from flash-spun, polythylene, film-fibril plexifilammentary strands. Du Pont brochure, E-32814, entitled "For hazardous or dirty jobs . . . protect your workers with garments of "TYVEK" Spunbonded Olefin", discloses garments made from the spunbonded olefin nonwoven sheets laminated with coextruded multilayered thermoplastic film (e.g., "Saranex", sold by Dow Chemical Company) along with the permeation characteristics of these laminated sheets. A Dow Chemical Company brochure, entitled "About Films of Saranex", describes "Saranex" as a layer of "Saran", integrally sandwiched between layers of polyethylene. This three-layered product is extruded as a single film without orientation. "Saranex 23" film differs from other "Saranex" products in that the "Saran" is coated on one side with low density polyethylene and on the other side with ethylene vinylacetate/low density polyethylene copolymer. "Saran" is a copolymer of vinyl chloride and vinylidine chloride.
Although the known protective garments have enjoyed some commercial success, there is need for fabrics that would provide protective garments with more time before hazardous substances could pass through the fabric (i.e., increase the so-called "hold-out time" of the substances by the fabric). Accordingly, an object of this invention is to provide such an improved fabric to enhance the utility of protective garments.